In many applications, differential signals are transmitted through different paths (i.e., cables), which have different characteristics (i.e., lengths). These differences in signal paths can create skew (known as intra-pair skew) between the complementary portions of the differential signal, which can adversely affect performance (especially in high speed applications). Conventionally, analog de-skewing circuits generally employ filters as delay elements (such as the low-pass filter 100 of FIG. 1, which uses resistor R1 and capacitor C2). While such filters do delay of the portions of the differential signal, these filters can have significant frequency attenuation which adversely affects the rise and fall times of the portions of the differential signal, as can be seen in FIG. 2. Thus, there is a need for a delay element and de-skew circuit with better performance characteristics.
Some other conventional circuits are: U.S. Pat. No. 7,493,509; U.S. Pat. No. 4,210,882; U.S. Pat. No. 7,085,337; U.S. Patent Pre-Grant Publ. No. 2007/0164802; and PCT Publ. No. WO2004/039023.